Calen P. Ryan, PhD

Contact information
[email protected]


Associate Research Scientist, Robert N. Butler Columbia Aging Center

Dr. Ryan is an associate research scientist in the Butler Columbia Aging Center in the Mailman School of Public Health. His research is centered on the role of epigenetic processes in development, reproduction, and aging. His work in the Philippines and elsewhere explores the impact of reproduction on the pace of biological aging, and the long-term effects of early life socioeconomic inequality. Dr. Ryan is currently studying stability and change in the epigenome in response to caloric restriction and developing new tools for studying metabolic rate using DNA methylation. His work has been featured in popular media including The Washington Post, BBC, and NBC, and has been supported by the National Science Foundation, the National Institute on Aging, the National Institute of Environmental Health Sciences, and the Natural Sciences and Engineering Research Council of Canada.


Education & Training:

PhD, 2020, Northwestern University

MA, 2014, Northwestern University

MSc, 2013, Simon Fraser University

BSc, 2010, (Hons), University of Manitoba


Honors and Awards:

Natural Sciences and Engineering Research Council of Canada (NSERC)

Harold E. Welch Award, Faculty of Science, University of Manitoba


Areas of Expertise
Evolution, Reproduction, Epigenetics, Data Science


Selected Publications:

Waziry, R., Ryan, C.P. et al. (2023) ‘Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial’, Nature Aging, 2023. doi: 10.1038/s43587-022-00357-y

Ryan, C.P. et al. (2022) ‘Immune cell type and DNA methylation vary with reproductive status in women: possible pathways for costs of reproduction’, Evolution, Medicine, and Public Health, 10(1), pp. 47–58. doi:10.1093/emph/eoac003.

Ryan, C.P. (2020) ‘“Epigenetic clocks”: Theory and applications in human biology’, American Journal of Human Biology, p. 18. doi:10.1002/ajhb.23488.

Ryan, C.P. and Kuzawa, C.W. (2020) ‘Germline epigenetic inheritance: Challenges and opportunities for linking human paternal experience with offspring biology and health’, Evolutionary Anthropology: Issues, News, and Reviews, 29(4), pp. 180–200. doi:10.1002/evan.21828.

Ryan, C.P. et al. (2018) ‘Reproduction predicts shorter telomeres and epigenetic age acceleration among young adult women’, Scientific Reports, 8(1), p. 11100. doi:10.1038/s41598-018-29486-4.